1. Field of the Invention
The present invention relates to an imaging device and a control method for the imaging device capable of zoom driving for changing a focal length during exposure, that is, capable of so-called inter-exposure zoom photographing.
2. Description of the Related Art
A photographing method called inter-exposure zoom photographing has been known. In this inter-exposure zoom photographing, photographing is performed while a focal length of a photographing optical system is changed during one session of exposure. In this photographing method, a photographing view of angle is changed during photographing, and magnification of a subject image is changed with that and thus, an image in which a trace of the subject is stretched radially outward from a center of the subject image can be obtained. By means of the inter-exposure zoom, a taken image giving an effect of highlighting the major subject image rather than a background can be obtained.
As described above, the inter-exposure zoom photographing has a well-known photographing method. However, this is a technology requiring experiences of a photographer in a photographing operation interlocking with the zoom driving of a photographing lens. Particularly when the photographer manually performs zoom driving, it is not easy to perform photographing by synchronizing a zoom driving operation of the photographing lens and a photographing operation relating to start and end operations of exposure. In order to solve this, Japanese Patent Laid-Open No. 2010-164716 and Japanese Patent Publication No. 7-23949 disclose a technology for facilitating the inter-exposure zoom photographing by electrically controlling the zoom driving so as to synchronize the zoom driving and the photographing operation with each other.